The MATISSE maternal vaccine clinical study for RSV

A Phase 3 Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy.

About the MATISSE study

The MATISSE maternal vaccine clinical study wants to find out if giving expecting mothers an investigational vaccine for respiratory syncytial virus (RSV) is safe and could help protect their babies from RSV after they are born.


Healthy Pregnant


18-49 Years





What are we researching?

We are studying if an investigational RSV vaccine could activate a mother’s immune system to create protective defenses (antibodies) against RSV that would be passed on to their developing babies. We are working to understand if this vaccine is safe and if it could protect babies from RSV.

What is RSV?

RSV is a very common disease of the airways. For most people, RSV is often mild and causes wheezing, coughing, sneezing, and runny nose.

However, for some babies, RSV can be serious, and lead to trouble eating or breathing. This is especially true for infants who are premature or have heart or lung problems.

Are vaccines safe while pregnant?

In most countries, maternal vaccinations are a regular part of prenatal care, and pregnant mothers are often vaccinated for diseases like the flu, pertussis (whooping cough), and tetanus.

When an expecting mother is vaccinated, she passes on the defenses (antibodies) she builds from the vaccine to her developing baby. This is called a “maternal vaccination.” Maternal vaccinations are an important way to protect babies in the first few months of life.

Find out if you are eligible to participate

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How does it work?

Who can take part in the MATISSE study?

We are looking for expecting mothers and their soon-to-be-born babies to take part in this study. You might qualify if you:

• Are between 18 and 49 years old
• Are healthy and expecting a single healthy baby
• Are in your late second or early third trimester when you receive the study vaccine
• Are not planning on delivering your baby at home
• Are willing and able to attend health checks and follow instructions from your study team

You need to meet other requirements to participate and your study team will talk you through these requirements during a screening visit.

What happens during the MATISSE study?

If you qualify for the MATISSE study and decide to take part, you will receive one injection of either the investigational RSV vaccine (the vaccine we are studying) or a placebo. Volunteers do not get to choose which they receive. This decision will be made by chance, like flipping a coin. You have an equal chance of receiving either the investigational vaccine or the placebo.

A placebo looks just like the investigational vaccine and is given in the same way, but does not have active ingredients in it. Neither you nor your study team will know which you received. When some volunteers receive a placebo and some receive the investigational vaccine, scientists can compare these groups to better understand if changes in your health or your baby’s health are because of the investigational vaccine and not something else.

How long is the MATISSE study?

You will have around four health checks over the course of about 10 months after you receive the vaccine. Your baby will also have about six health checks during the first 24 months of their life. Your baby may also be seen if they get sick. Some of these checks may be done by phone.

Your study team will call you on the phone about once a week until your child is 6 months old, then about once a month for the rest of their time in the study. These checks are to see if your baby needs to see the doctor.

Other things to note

Clinical studies are your choice

You do not have to take part in the study if you don’t want to. If you decide to join, you can also change your mind and leave at any time. This will not affect you or your baby’s regular medical care.

While only you can make the decision to join the study, it may help to talk with your partner, family, or anyone else who might help you in raising your child before you decide.

What if my health or my baby’s health gets worse?

Before you join the MATISSE study, your team will tell you about the potential risks (or harms) and benefits of the study and get your permission to participate. During the study, it’s important to tell your study doctor about any changes in your health and your baby’s health as soon as you see them. This way, if anything happens, your study team can decide on the best way to protect the health of you and your baby.

I’m interested. What happens now?

If you would like to take part, the study team will give you a document that describes what to expect for you and your baby during this study. We encourage you to take this home and talk with your partner, family, and doctors about whether you should participate.

Please ask your study team questions if anything is unclear. Once you have read and understood the informed consent document, you can sign it if you would like to join the study.

Interested In Learning More?